Conclusion
Microemulsion reactor was used for lignin depolymerization in this work
for the first time, and the constructed octane/n -propanol/water
SFEM system has a much better efficiency by comparison with typical
solvent systems where 127.1 mg g-1 of phenolic
monomers is achieved under the optimized conditions. Characterizations
by UV-vis spectroscopy, FT-IR spectroscopy and Cryo-SEM indicate that
the solubility of lignin can be enhanced greatly in this microemulsion,
and the microemulsion droplets are enlarged from 48 to 75 nm by the
addition of lignin, due to the directional aggregation of lignin at the
interface of microemulsion, thereby to have this lignin depolymerization
process intensified. Furthermore, this system is appropriate for other
organosolv lignins oxidation and the performance of it is stable even
when lignin concentration is up to 40.8 g L-1.
Therefore, so constructed SFEM system can give a well example for highly
efficient depolymerization of lignin through a novel reactor and simple
process intensification strategy.